SAN FRANCISCO – If only it were just a June swoon. Then the Giants could feel better about themselves moving forward.

But here they are, with 72 hours left in July, going on two full months of being totally and inescapably unable to compete at AT&T Park. After appearing overmatched by the Dodgers in three games, the Giants went from dull and desultory to making downright dumb mistakes in an offensively impotent 5-0 loss to the Pittsburgh Pirates Monday night.

The Giants are 6-20 at home since June 9. When you do that, you’re not just throwing away a division. You’re threatening to bury yourself before rosters expand. And the sellout crowds are sounding less hopeful by the day. They’re heading for the gates earlier, too.

Madison Bumgarner was supposed to be a leaf turner but instead got blown out in a four-run, 42-pitch first inning that included his own throwing error on a pickoff throw that was better suited for blacktop dodgeball.

The Giants offense never regrouped even though they weren’t facing Cole Hamels, Zack Greinke, Clayton Kershaw or Hyun-Jin Ryu. Vance Worley, the Pirates’ bespectacled right-hander pitched to contact and the Pirates infield made one nimble play after another to help him throw his first career shutout on just 100 pitches.

Oh, and no, there was no good reason for Gregor Blanco to try to steal second base with the Giants down 5-0 in the sixth inning – especially against Russell Martin, one of the league’s best defensive catchers.

Starting pitching reportBumgarner (12-8) didn’t really get an All-Star break, and not just because he attended the festivities in Minnesota. He had four days between starts before and after the break, whereas the rest of the Giants rotation had at least eight days. Bumgarner also endured a rain delay in his previous start at Philadelphia heading into Monday’s outing.

That’s not an excuse for his five runs in four innings. It’s more to wonder whether the Giants should have just pulled him after the first.

It started with the bases loaded and no outs after two walks and a single. Gaby Sanchez hit a sacrifice fly and Neil Walker lined an RBI single up the middle. Bumgarner had Andrew McCutchen picked off second base, but he held onto the ball too long and then skipped a throw that hit the runner as he dived back to the bag. It ricocheted away, allowing McCutchen to take third on the error.

Russell Martin followed with an RBI single and Gregory Polanco lifted a sacrifice fly to right field. Catcher Buster Posey couldn’t handle the two-hop throw, then didn’t even react as it squirted away for an error that allowed Martin to take second base.

Bumgarner allowed a home run to Josh Harrison in the second inning before retiring eight of the last nine batters he faced. He finally found a groove, but it came far too late.

His 42 pitches in the first inning was a career high.

Bullpen reportYusmeiro Petit began warming up in the first inning. He entered in the fifth. Mercifully, he tossed two perfect innings and the Giants pieced it together from there.

At the plateThe Giants’ inability to score at home is threatening to take down their season, if their other deficiencies don’t get them first. They entered having scored just 2.76 runs per game while losing 19 of 25 at home, and they batted .227 over that stretch.

Nowhere is the loss of leadoff man Angel Pagan more sorely felt than here at AT&T Park, where they need to move runners and string together hits to score. This offense just doesn’t work here without him, and that’s become more apparent by the day.

Pablo Sandoval singled in the fifth inning to break up Worley’s bid, then promptly got rubbed out when Michael Morse grounded into a double play. Walker, the Pirates’ second baseman bent his body to catch a bad feed while keeping his foot on the base, then fired quickly for the out.

Sandoval singled in the eighth and Morse bounced into a fielder's choice. The Giants would have gone the entire game without a runner in scoring position if not for Hunter Pence's two-out triple in the ninth.

The Giants’ other hit? Blanco in the sixth. That did not end well.

Worley, who hails from Sacramento, needed just 100 pitches to throw his first career shutout.

Morse, by the way, has one home run since June 5 – his arm-thrusting shot off Huston Street in San Diego on July 5. His last homer at AT&T Park came on May 15. He hit four homers in his first 19 home games, and has zero in his last 38.

In fieldErrors on Posey and Bumgarner didn’t make a massive difference on the scoreboard, but it made a ragged first inning feel even worse.

AttendanceWith an official crowd of 41,794, the Giants extended their streak of announcing sellouts to 303 consecutive regular-season games. The no refund-policy remains in place.